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From: Jonathan Wakely <jwakely.gcc@gmail.com>
Date: Fri, 1 May 2020 12:39:58 +0100
Message-ID: <CAH6eHdSoRe+rLnx5r=6ijxgsCPEzO7h3rEf_z2=Nc7wWVBWDNg@mail.gmail.com>
Subject: Re: -fsanitize=undefined behavior
To: Tom N <nospam@codesniffer.com>
Cc: gcc-help <gcc-help@gcc.gnu.org>
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On Thu, 30 Apr 2020 at 23:58, Tom N <nospam@codesniffer.com> wrote:
>
> > On April 30, 2020 at 5:57 PM Jonathan Wakely <jwakely.gcc@gmail.com> wrote:
> > The man page says:
> > "Unlike other similar options, -fsanitize=float-divide-by-zero is not enabled by -fsanitize=undefined" and "Unlike other similar options,-fsanitize=float-cast-overflow is not enabled by -fsanitize=undefined"
> > So it seems reasonable to assume that all the other suboptions are enabled by -fsanitize=undefined, and if you want *all* of them then use -fsanitize=undefined -fsanitize=float-divide-by-zero-fsanitize=float-cast-overflow
>
> Thanks for the tip.  Any reason the description of -fsanitize=undefined doesn't include something like, "If the -fsanitize=undefined option is enabled all sub-options will be enabled unless otherwise specified." so it's clear?

Probably because nobody has suggested doing that yet. Would you like
to propose a patch for the docs?

The relevant place is here:
https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/doc/invoke.texi;h=527d362533ab503cee9568b27808177977a52ac8;hb=HEAD#l13541